1. Field of the Invention
The present invention relates generally to regenerative braking, and in particular, to actuating regenerative braking to recharge a battery of an electric or hybrid electric vehicle while the vehicle is being towed.
2. Discussion of the Prior Art
It is known to tow one vehicle with another vehicle. The circumstances surrounding the towing vary substantially. One common circumstance where one vehicle is towed by another is the case where a recreational vehicle (RV) tows a smaller vehicle, typically for local transportation when the RV is parked at a destination.
Where an automobile is the towed vehicle, a trailer is often used for the towing, to prevent damage to the transmission of the vehicle. Most states regulate the towing of vehicles, particularly where the towed vehicle exceeds a certain weight. This is because safety becomes a concern where the towed vehicle exceeds a certain weight. Typically, the regulations for heavy vehicles include that the towed vehicle be configured to brake when the towing vehicle brakes. Hence, a signal proportional to the braking on a towing vehicle is received on a trailer that is being towed to selectively brake the trailer.
Electric vehicles, including hybrid electric vehicles, produce electricity and braking torque by using a traction motor as a generator during braking. This is called regenerative braking. Energy produced by regenerative braking is used to charge a battery on the vehicle. These electric vehicles reduce the amount of emissions in the environment and increase gas mileage. In some hybrid and other electric vehicles, a regenerative braking system is used in addition to the hydraulic braking system typically used in internal combustion engine vehicles.
The proliferation of hybrid and other electric vehicles provides many opportunities to exploit the new and useful characteristics associated with these vehicles. One such adaptation is disclosed herein where the regenerative braking features of a towed electric vehicle are use to simultaneously charge a vehicle and brake a vehicle during towing, advantageously conserving energy and providing safety.